Many surgical procedures require vessels or other tissues of the human body to be ligated during the surgical process. For example, many surgical procedures require cutting blood vessels (e.g., veins or arteries), and these blood vessels may require ligation to reduce bleeding. In some instances, a surgeon may wish to ligate the vessel temporarily to reduce blood flow to the surgical site during the surgical procedure. In other instances a surgeon may wish to permanently ligate a vessel. Ligation of vessels or other tissues can be performed by closing the vessel with a ligating clip, or by suturing the vessel with surgical thread. The use of surgical thread for ligation requires complex manipulations of the needle and suture material to form the knots required to secure the vessel. Such complex manipulations are time-consuming and difficult to perform, particularly in endoscopic surgical procedures that afford limited space and visibility. By contrast, ligating clips are relatively easy and quick to apply. Accordingly, the use of ligating clips in both endoscopic and open surgical procedures has grown dramatically.
Various types of hemostatic and aneurysm clips are used in surgery for ligating blood vessels or other tissues to stop the flow of blood. Such clips have also been used for interrupting or occluding ducts and vessels in particular surgeries such as sterilization procedures. Typically, a clip is applied to the vessel or other tissue by using a dedicated mechanical instrument commonly referred to as a surgical clip applier, ligating clip applier, or hemostatic clip applier. A clip applier designed for use with asymmetric plastic clips in an open (i.e., non-endoscopic) surgical procedure is disclosed in U.S. Pat. No. 5,100,416 to Oh et al., assigned to the assignee of the present invention. The clip applier is used to position the clip over the desired vessel and its jaws are actuated, typically using an actuating mechanism disposed in the handle of the device, to close the clip about the vessel. The clip is typically left permanently in place after application to the tissue. In other cases, at some point after hemostasis or occlusion occurs, the clip can be removed if required by using a separate instrument dedicated for that purpose, i.e., a clip removal instrument.
Ligating clips can be classified according to their geometric configuration (e.g., symmetric clips or asymmetric clips), and according to the material from which they are manufactured (e.g., metal clips or polymeric clips). Symmetric clips are generally “U” or “V” shaped and thus are substantially symmetrical about a central, longitudinal axis extending between the legs of the clip. Symmetric clips are usually constructed from metals such as stainless steel, titanium, tantalum, or alloys thereof. By means of a dedicated clip applier, the metal clip is permanently deformed over the vessel. An example of one such clip is disclosed in U.S. Pat. No. 5,509,920 to Phillips et al. An example of a metallic clip applier is disclosed in U.S. Pat. No. 3,326,216 to Wood, in which a forceps-type applier having conformal jaws is used to grip and maintain alignment of the clip during deformation. Such appliers may additionally dispense a plurality of clips for sequential application, as disclosed in U.S. Pat. No. 4,509,518 to McGarry et al.
With the advent of high technology diagnostic techniques using computer tomography (CATSCAN) and magnetic resonance imaging (MRI), metallic clips have been found to interfere with the imaging techniques. To overcome such interference limitations, biocompatible polymers have been increasingly used for surgical clips. Unlike metallic clips, which are usually symmetric, polymeric clips are usually asymmetric in design and hence lack an axis of symmetry. Inasmuch as the plastic clip cannot be permanently deformed for secure closure around a vessel or other tissue, latching mechanisms have been incorporated into the clip design to establish closure conditions and to secure against re-opening of the vessel. For example, polymeric clips are disclosed in U.S. Pat. No. 4,834,096 to Oh et al. and U.S. Pat. No. 5,062,846 to Oh et al., both of which are assigned to the assignee of the present invention. These plastic clips generally comprise a pair of curved legs joined at their proximal ends with an integral hinge or heel. The distal ends of the curved legs include interlocking latching members. The distal end of one leg terminates in a lip or hook structure into which the distal end of the other leg securely fits to lock the clip in place. The distal ends of the clips taught by Oh et al. also include lateral bosses that are engaged by the jaws of the clip applier.
A clip applier specifically designed for asymmetric plastic clips, such as the aforementioned U.S. Pat. No. 5,100,416 to Oh et al., is used to close the clip around the tissue to be ligated, and to latch or lock the clip in the closed condition. In operation, the jaws of this clip applier are actuated into compressing contact with the legs of the clip. This causes the legs to pivot inwardly about the hinge, thereby deflecting the hook of the one leg to allow reception therein of the distal end of the other leg.
In addition to compatibility with sophisticated diagnostic techniques, asymmetric clips have other advantages over symmetric clips. For example, because asymmetric clips are formed from polymeric materials, the mouths of asymmetric clips can be opened wider than the mouths of symmetric clips. This allows a surgeon to position the clip about the desired vessel with greater accuracy. In addition, a clip of the type described in U.S. Pat. Nos. 4,834,096 and 5,062,846 can be repositioned before locking the clip on the vessel or before removing the clip from the vessel, in a process referred to as “approximating” the clip.
As indicated above, U.S. Pat. No. 5,100,416 to Oh et al. discloses a clip applier designed for use with asymmetric plastic clips in an open (i.e., non-endoscopic) surgical procedure. Other types of clip appliers have been developed for applying metallic clips. Clip appliers can also be classified according to whether they are designed for either open surgical procedures or endoscopic surgical procedures. Clip appliers designed for use with metallic clips in open surgery are disclosed in U.S. Pat. No. 3,270,745 to Wood; U.S. Pat. No. 3,326,216 to Wood; U.S. Pat. No. 3,439,522 to Wood; U.S. Pat. No. 3,439,523 to Wood; U.S. Pat. No. 4,146,130 to Samuels et al.; U.S. Pat. No. 4,646,740 to Peters et al. (assigned to the assignee of the present invention); U.S. Pat. No. 4,509,518 to McGarry et al.; U.S. Pat. No. 5,047,038 to Peters et al. (assigned to the assignee of the present invention); and U.S. Pat. No. 5,104,395 to Thornton et al. (assigned to the assignee of the present invention). Clip appliers designed for use with metallic clips in endoscopic surgery are disclosed in U.S. Pat. No. 5,403,327 to Thornton et al.; U.S. Pat. No. 5,112,343 to Thornton; U.S. Pat. No. 5,527,320 to Carruthers et al.; and U.S. Pat. No. 5,634,930 to Thornton et al., all of which are assigned to the assignee of the present invention.
Clip appliers can be further classified according to whether they are manual or automatic. The term “automatic” denotes the kind of clip appliers designed to retain a plurality of hemostatic clips in proximal relation to the jaws of a clip applier. A new clip is automatically fed to the jaws after the previous clip has been crimped or latched into place. Automatic clip appliers are disclosed in the aforementioned U.S. Pat. Nos. 4,509,518; 4,646,740; 5,047,038; 5,104,395; 5,112,343; 5,403,327; 5,527,320; and 5,634,930.
By contrast, the term “manual” denotes the kind of clip appliers that receive one clip at a time between the jaws, and which must be reloaded manually after the previous clip has been crimped or latched. These manual instruments usually have a forceps-type design. The reloading operation is generally accomplished by inserting the jaws of the applier into a clip holder or cartridge that is a physically separate component from the clip applier itself. Many types of clip cartridges currently available contain a plurality of longitudinally-spaced clip-retaining chambers. A single clip is retained in each chamber by a variety of means, and is removed from its chamber by inserting the jaws of the clip applier into the selected clip chamber to engage or grasp the clip sufficiently to overcome whatever clip retention means is utilized, thereby enabling the clip to be removed from the clip chamber. Manual clip appliers are disclosed in the aforementioned U.S. Pat. Nos. 3,270,745; 3,326,216; 3,439,522; 3,439,523; 4,146,130; and 5,100,416.
Conventional clip appliers of all types discussed above typically include a pair of jaws, and a handle or grip assembly designed for manipulation by the hand and fingers of the user to actuate the jaws. In addition, an elongate (e.g., 11 inches) intermediate section separates the jaws and the handle assembly. This intermediate section is usually a shaft section in the case of automatic and/or endoscopic clip appliers, or a pair of pivoting arms in the case of most manual clip appliers. In the case of most automated and/or endoscopic clip appliers, some type of linkage is provided in the shaft section and/or the handle assembly through which the force imparted by the surgeon's hand to move the handles (e.g., squeezing) is transferred into, pivoting of the jaws and thus compression of the clip.
A typical automated clip applier is operated by executing a forward stroke and a subsequent return stroke. The forward stroke loads a clip into the jaws of the clip applier and applies the clip to a target vessel or other tissue at the surgical site. The return stroke resets the clip applier for subsequent manipulation of the next available clip stored within the instrument. The forward stroke is executed by squeezing the handles of the instrument to actuate various components thereof. The return stroke is executed by releasing hand pressure on the handles to cause certain components to return to a starting position. At some point during either the forward stroke or the return stroke, the several clips typically stored in the shaft section of the instrument must be advanced toward the jaws in preparation for loading the next available clip into the jaws. The successful operation of such automated clip appliers necessarily requires the use of moving and often reciprocating components, many of which must interact with each other and/or with the clips. Moreover, the moving components must carry out their respective functions without interfering with the advancement and alignment of the clips through the shaft section and the sequential loading of the clips into the jaws, and without failing during a surgical procedure. Accordingly, it is well recognized among persons skilled in the art that a continuing need exists for improvements in the design and operation of automated-feed clip appliers.